Atomstroiexport chief Leonid Reznikov said that by year’s end the company will take steps that will make the launch of the Bushehr plant "irreversible," said AP.
Company spokeswoman Irina Yesipova said the launch date will be determined after talks between Russian and Iranian nuclear officials this month.
Iranian officials have said that Bushehr would be launched this fall.
The International Atomic Energy Agency declined comment, the AP said.
Iran is paying Russia more than $1 billion to build the 1,000-megawatt light-water reactor. Construction has been held up by disputes between Tehran and Moscow, publicly described as centering on questions of payment and the schedule for shipping nuclear fuel.
The United States and other Western nations that fear Iran is seeking to acquire nuclear weapons have criticized Russia for building Bushehr.